On 2/1/13 7:18 AM, Pawel Moll wrote:
8<---
From 2ad51a27fbf64bf98cee190efc3fbd7002819692 Mon Sep 17 00:00:00 2001
From: Pawel Moll <pawel.m...@arm.com>
Date: Fri, 1 Feb 2013 14:03:56 +0000
Subject: [PATCH] perf: Add ioctl to return current time value
To co-relate user space events with the perf events stream
a current (as in: "what time(stamp) is it now?") time value
must be made available.
This patch adds a perf ioctl that makes this possible.
Are there any objections to this approach? I need a solution for my
time-of-day patch as well.
David
Signed-off-by: Pawel Moll <pawel.m...@arm.com>
---
include/uapi/linux/perf_event.h | 1 +
kernel/events/core.c | 8 ++++++++
2 files changed, 9 insertions(+)
diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
index 4f63c05..b745fb0 100644
--- a/include/uapi/linux/perf_event.h
+++ b/include/uapi/linux/perf_event.h
@@ -316,6 +316,7 @@ struct perf_event_attr {
#define PERF_EVENT_IOC_PERIOD _IOW('$', 4, __u64)
#define PERF_EVENT_IOC_SET_OUTPUT _IO ('$', 5)
#define PERF_EVENT_IOC_SET_FILTER _IOW('$', 6, char *)
+#define PERF_EVENT_IOC_GET_TIME _IOR('$', 7, __u64)
enum perf_event_ioc_flags {
PERF_IOC_FLAG_GROUP = 1U << 0,
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 301079d..4202b1c 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -3298,6 +3298,14 @@ static long perf_ioctl(struct file *file, unsigned int
cmd, unsigned long arg)
case PERF_EVENT_IOC_SET_FILTER:
return perf_event_set_filter(event, (void __user *)arg);
+ case PERF_EVENT_IOC_GET_TIME:
+ {
+ u64 time = perf_clock();
+ if (copy_to_user((void __user *)arg, &time, sizeof(time)))
+ return -EFAULT;
+ return 0;
+ }
+
default:
return -ENOTTY;
}
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
